Fogstar Drift 100Ah vs Renogy 200Ah — anyone actually run both long-term?

So I've been down a proper rabbit hole this week trying to spec the battery bank for my shepherd's hut build. Currently running a single Fogstar Drift 100Ah in my Vivaro (hence the username, obviously) paired with a Victron SmartSolar 100/20, and honestly it's been brilliant — three years, zero drama, still showing 99% SoH on the Victron app.

The hut is a different beast though. I'm thinking I need something closer to 400Ah usable to cover a couple of nights without sun, run a small inverter for the kettle and laptop, and eventually trickle-charge an EV overnight when I get my act together. Fogstar's own 200Ah Drift units are tempting because I already trust the brand, but the Renogy 200Ah keeps coming up and it's often a solid chunk cheaper on Amazon.

The thing that's nagging at me is the BMS behaviour under load. I've read horror stories about cheaper LiFePO4 BMS units tripping at awkward moments — mid-brew, mid-Teams call, you name it. Has anyone actually stress-tested both and compared how gracefully they handle surge loads from a 1000W+ inverter?

Genuinely curious whether the Fogstar premium is worth it here or if I'd be paying for peace of mind I don't actually need.

@VivaroNomad the narrowboat is where I've done most of my long-term testing, so slightly different use case to yours, but the principles stack up.

Ran a Renogy 200Ah for about eighteen months before swapping to a pair of Fogstar Drifts. The Renogy did the job, never complained — but the BMS felt a bit opaque. Couldn't pull meaningful data from it without jumping through hoops.

The Drifts talk to my Victron kit properly, which for a shepherd's hut where you're not always on-site makes a real difference. You want to see what's happening remotely, not come back to a mystery.

One thing nobody mentions — the Fogstar's slightly lower capacity hurts less than you'd expect because the usable percentage is genuinely better in real conditions. Two 100Ah cells have been noticeably more consistent than that single 200Ah ever was.

@VivaroNomad ran a Fogstar Drift 100Ah in the van for 18 months before doubling up, and honestly the only thing that let it down was my inability to stop running the kettle at midnight — the cell itself was flawless.

For a shepherd's hut though, you've got the luxury of space, so the Renogy 200Ah starts making sense purely on cost per Ah unless you're precious about weight.

Static install = weight is irrelevant, so I'd probably go Renogy, stick a Victron SmartShunt on it, and spend the savings on a decent MPPT.

@VivaroNomad ooh shepherd's hut build, that sounds brilliant — how are you planning to handle the roof space for panels?

Genuine question actually, because I'm mid-spec on a tiny house right now and facing a similar dilemma. I've got a Fogstar Drift in the motorhome and it's been solid, but I'm wondering whether for a static install like a shepherd's hut you'd be better off going with two Drifts in parallel rather than jumping to the Renogy? You'd keep the flexibility to start small and expand, plus Fogstar's warranty support has been decent from what I've seen on here.

What's your expected daily consumption looking like? That'll probably drive the decision more than the brand comparison — have you run the numbers through a solar calc yet?

@VivaroNomad been running four Fogstar Drift 100Ah cells in parallel on my narrowboat for just over two years now, so reasonably long-term. They've been rock solid honestly — never had a BMS trip I couldn't explain, and capacity degradation has been minimal.

One thing worth knowing for the shepherd's hut specifically: temperature management matters more in a static build than a van. My boat stays relatively stable but a hut can get absolutely baltic in winter. The Drifts handle low temps better than some cheaper cells I've tried, but you'll still want to think about where you're positioning the bank.

Haven't run the Renogy 200Ah personally so can't do a direct comparison, but I'd be curious what @DorsetCamper found on the narrowboat — similar static environment, probably relevant to your situation.

@BoatShaun that's really useful — narrowboat is exactly my use case too so good to hear the Drift cells holding up long-term. Quick question though: have you noticed any cell drift (no pun intended) between the four units over that time, and does your BMS handle balancing okay without intervention?

Also wondering about discharge rates — on the narrowboat I'm occasionally running an EV charger off the bank when we're moored up with shore power unavailable, so peak draw can spike quite high. Anyone pushed the Fogstar Drift hard on sustained high-current discharge and seen any thermal issues or BMS trips?

The Renogy 200Ah is tempting purely for the single-unit simplicity but I can't find anyone who's actually stress-tested it in a marine environment rather than a garden setup.

@VivaroNomad ran a Renogy 200Ah in my last van conversion for 18 months before switching to Fogstar Drift cells — the Renogy's fine until it isn't, whereas the Drift just quietly gets on with it like a reliable Northern relative who never asks for anything.